1. Field of the Invention
This invention relates to an improved design of a pressure amplifier or converter for mounting above the drill bit at the lower end of a drill pipe for deep drilling, in particular for oil and gas, and for generating an increased fluid pressure by utilizing energy from the flow of drilling fluid downwards through the drill string and the drill pipe. This may be, inter alia, for the purpose of obtaining an enhanced drilling effect, preferably by means of one or more high pressure jets adapted to have a cutting effect in the surrounding rock.
2. Description of the Related Art
The invention can be regarded as a further development and improvement of structures described in Norwegian Patent Specification Nos. 169.088, 171.322, 171.323 and 171.325. Norwegian Patent 171.323 is particularly directed to a valve assembly for this type of pressure converter, which advantageously can be replaced by the new and improved designs described below. The new designs involve, inter alia, less wear of vital valve parts and better reliability and safety under the extreme conditions that the structures are subjected to in use.